Ferrari mechanics work on Fernando Alonso's car after he was forced to cut his first practice session short in China. Photograph: Franck Robichon/EPA

The two-time world champion Fernando Alonso insisted he was unconcerned by a second engine failure in as many weeks during today's first practice session for the Chinese grand prix, saying he was confident it would not affect his chances of victory this weekend.

Alonso had to cut short his run in morning practice after smoke started billowing from his exhaust, raising fears Ferrari had not got to the bottom of their engine issues after a similar problem ended his race in Malaysia earlier this month. The engine that failed today was the one removed in Bahrain following an overheating issue and Alonso admitted he expected a problem to occur.

"I am not worried," he said. "We lost an engine today, which is never a good thing, we would like to have all the engines perfectly OK. We knew that this engine was a little bit damaged after Bahrain, it was the one we replaced in Bahrain before the race so we are not too worried.

"The problems mean that on the Fridays from now on we will use old engines. The race engines will be the original plan we set in January. Very fresh engines and not a problem. Everything is going according to plan so far. Unfortunately we lost two engines, this one was maybe expected but the one in Malaysia was a surprise."

Alonso returned to the circuit in the second session with a new engine and clocked the 10th fastest lap and the 28-year-old believes he can be competitive in tomorrow's qualifying.

"I don't see any reason why we can't be optimistic tomorrow," he added. "It is pointless looking at today's timesheet, because each team follows its own work programme and that makes it impossible to compare the times. We stuck to our plan and we are pretty happy with what we achieved. I think we will be competitive at this track."

The current drivers' championship leader, Felipe Massa, was 10th and 11th fastest in the two sessions and he shared his team-mate's optimism that Ferrari can be competitive, but is expecting a close fight with his rivals in qualifying.

"I am satisfied with the way this free practice day went," said the Brazilian. "We did a lot of kilometres, concentrating mainly on preparing the car for Sunday's race. I think several teams are going to be very competitive, not just McLaren and Red Bull, but also Mercedes who have made a step forward. Let's hope we will be in the fight with them."